Semiconductor memory is widely used in various electronic devices such as mobile computing devices, mobile phones, solid-state drives, digital cameras, personal digital assistants, medical electronics, servers, and non-mobile computing devices. Semiconductor memory may comprise non-volatile memory or volatile memory. A non-volatile memory system allows information to be stored or retained even when the non-volatile memory system is not connected to a source of power (e.g., a battery).
One type of non-volatile memory cell is a reversible-resistance memory cell. A reversible-resistance memory cell may be repeatedly switched between two or more resistance states. The process of switching the resistance of a reversible-resistance memory cell from a high-resistance state to a low-resistance state may be referred to as setting the reversible-resistance memory cell. The process of switching the resistance from the low-resistance state to the high-resistance state may be referred to as resetting the reversible-resistance memory cell.
The resistance state that a reversible-resistance memory cell is in immediately after fabrication will be referred to herein as a “virgin” resistance state. Some reversible-resistance memory cells are in a high resistance state immediately after fabrication. The first time that such reversible-resistance memory cells are switched from the “virgin” high resistance state to a low resistance state is typically referred to as a “forming” operation. Some reversible-resistance memory cells are in a low resistance state immediately after fabrication. Such memory cells may be switched from the “virgin” low resistance state to a high resistance state. The first time that such reversible-resistance memory cells are switched from the virgin low resistance state to a high resistance state may be referred to herein as an “initialization” operation.